T1L5: Muscle systems

Question 1

Contractile proteins

Answer 1

Contractile proteins (myofilaments) arranged as myofibrils

Question 2

Skeletal muscle

Answer 2

Elongated and multinucleated
Peripheral nuclei
CT: Epimysium, Perimysium and endomysium
Bundles = fascicles
Epimysium surrounds entire muscle, Perimysium surrounds fascicles
Regenerate - satellite cells

Question 3

Flat

Answer 3

Parellel fibres within an apernosis, e.g external oblique

Question 4

Pennate

Answer 4

feather like may be unipennate, bipennate or mutilpennate e.g. flexor digitorium

Question 5

Fusiform

Answer 5

spindle shaped with round bellie and tappered at tendons

Question 6

Circular

Answer 6

orricucle, obicularis oris

Question 7

Muscles

Answer 7

Flat
Pennate 
Fusiform
Circular 
Quadrate

Question 8

Myocardium

Answer 8

• Function: continuous rhythmic contractions to pump blood from the heart
  
  • Continuous into adjacent portions of the great vessels
  • Intrinsically generated contractions modified by the autonomic nervous system (ANS)
  • Parasympathetic (via Vagus nerve) decreases HR
  • Central nuclei + Branching pattern + Cells connected by intercalated discs
  Myofibrils less defined and no defined connective tissue layer

Question 9

Intercalated discs contain [2]

Answer 9

1. Fascia adhesions (Desmosomes allow coordination of contraction)

Gap junctions (allow fast conduction and dissemination of Action Potential)

Question 10

Visceral

Answer 10

• Function: slow sustained contractions to move contents through viscera
  
  • Low force
  • Contractions may be rhythmic or wave like
  • Stimulated by:
  • Autonomic NS
  • Hormones

Question 11

Smooth muscle

Answer 11

• Spindle shaped
• Single central nuclei
• Branching pattern
• Contractile proteins not arranged as myofibrils/sacromeres
• Proteins criss-cross and anchor to focal densities
• Cells run parallel to force of contraction
Has a supporting network of connective tissue